Efeito do parasitismo por Digenea na atividade locomotora de peixes e moluscos hospedeiros. 2013.

Abstract

Parasites are able to alter various caractheristics of the hosts, among them behavior, morphology and social structures. Process of behavioral changes are commonly found in parasites that have complex life’s cycle, which transmission occur through of the trophic web. Aquatic organisms are commomly used in behavioral assays and fish and molluscs are considered as good models in this surveys. In Chapter I, we showed a survey which assess the influence of the intensity and period development of Ascocotyle (Phagicola) pindoramensis on locomotory activity of Poecilia vivipara born in laboratory. Similarly, in Chapter II, a comparative study was performed with objective of assess the influence of the parasitism on locomotory activity of Melanoides tuberculatus uninfected and naturally infected by Centrocestus formosanus. The locomotory activity of fishes and molluscs were monitored through image analysis biomonitoring system, Videomex-V®, linked to with a video camera able to record and quantify the distance travelled, moving or restintg time and speed of the organims. The Generalized Estimating Equations (GEE) able to analyse data with repeated mesuares showed that although infected molluscs by C. formosanus had showed higher length shell than unfected ones, both the length of M. tuberculatus as P. vivipara do not was important factor to alter the locomotory activity of the intermediate hosts. Infected hosts showed a pattern of locomotory activity irregular and reduced when compare to uninfected ones. Furthermore, P. vivipara do not alters locomotory activity at 7 days post-infection (dpi), but the alterations become evident at 14 dpi, showing an increase on the resting time. It was experimentally showed that in P. vivipara higher parasites intensity decreased the locomotory activity of the host. The parasites studied are able to alter the locomotor behavior of P. vivipara and M. tuberculatus. It is surmised that the decrease of locomotory activity of the hosts can interfer differents aspects in an ecological context in the natural environment.